The Fishing.jmp sample data table contains fictional data for a study of various factors that affect the number of fish caught by groups visiting a park. The data table contains 250 responses from families or groups of traveling companions. This example models the number of Fish Caught as a function of Live Bait, Fishing Poles, Camper, People, and Children. These columns are described in Column Notes in the data table.
The data table contains a hidden column called Fished. During data collection, it was never determined whether anyone in the group had actually fished. However, the Fished column is included in the table to emphasize the point that catching zero fish can happen in one of two ways: Either no one in the group fished, or everyone who fished in the group was unlucky.
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Select Analyze > Fit Model.
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Terms up to degree 2 (the default in the Degree box) are added to the model.
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From the Personality list, select Generalized Regression.
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From the Distribution list, select ZI Poisson.
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Click Run.
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From the Estimation Method List, select Elastic Net.
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Click Go.
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An Adaptive Elastic Net with Validation Column report appears. The Solution Path, the Parameter Estimates for Original Predictors report, and the Effect Tests report indicate that a number of terms are zeroed. The Zero Inflation parameter, whose estimate is shown on the last line of both Parameter Estimates reports, is highly significant. This indicates that some of the variation in the response, Fish Caught, might be due to the fact that some groups did not fish.
The Effect Tests report indicates that four terms are significant at the 0.05 level: Live Bait, Fishing Poles, Fishing Poles*Camper, and Fishing Poles*Children.
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Click the red triangle next to Adaptive Elastic Net with Validation Column and select Profilers > Profiler.
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Click the Prediction Profiler red triangle menu and select Optimization and Desirability > Desirability Functions.
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A function is imposed on the response, which indicates that maximizing the number of Fish Caught is desirable. (See Desirability Profiling and Optimization the Profilers book for more information about desirability functions.)
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Click the Prediction Profiler red triangle menu and select Optimization and Desirability > Maximize Desirability.
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You can vary the settings of the predictors to see the impact of the significant effects: Live Bait, Fishing Poles, Fishing Poles*Camper, and Fishing Poles*Children. For example, Live Bait is associated with more fish; a Camper tends to bring more fishing poles than someone who is not camping and therefore catches more fish.
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Click the red triangle next to Adaptive Elastic Net with Validation Column and select Save Columns > Save Prediction Formula and Save Columns > Save Variance Formula.
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Right-click either column heading and select Formula to view the formula. Alternatively, click the plus sign to the right of the column name in the Columns panel. Note the appearance of the estimated zero-inflation parameter, 0.7843639, in both of these formulas.
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